Summary of Work: The study of oxidative stress has attracted considerable interest and has been the focus of much research in recent years. Cumulative oxidative damage to tissues has been implicated in a number of disease states, e.g. the aging process, cancer, and ischemia reperfusion. The study of oxidative stress in the mitochondria has shown that hydrogen peroxide is produced via the incomplete reduction of oxygen during oxidative phosphorylation. Hydrogen peroxide levels are kept relatively low under normal physiological conditions. Under certain conditions, such as inflammation, excessive amounts of hydrogen peroxide are produced. The production of excess hydrogen peroxide is thought to precede several occurrences, such as lipid peroxidation, DNA and/or protein damage, and glutathione depletion, that are characteristic of oxidative stress. In a long-term collaboration with the epr group (Mason/LPC) we have been investigating the sites of radical formation on proteins and peptides and have been determining the specific site on the amino acid which undergoes radical formation during oxidation by determining the structure of the amino acid spin-trap covalent adduct. This information is important to our understanding of the damage that can occur by free-radical oxidation of proteins and how that damage occurs. Investigation of the mechanism of development of Parkinson's disease: In collaboration with R. Mason (LPC) and G. Pielak (UNC), we are involved in a project whose aims is to probe how a-synuclein undergoes Lewy body formation. The working hypothesis is that oxidative damage to heme proteins such as cyt c leads to release of the cyt c from the mitochondria. Upon release, the cyt c free radical can react further with other proteins, such as a-synuclein. These secondary free-radical proteins can then undergo either chemical cross-linking or conformational changes that lead to aggregation.